Viltolarsen NDA Accepted for Filing by the FDA
NS Pharma announced that the U.S. Food & Drug Administration (FDA) has accepted the filing of their New Drug Application (NDA) for viltolarsen (NS-065/NCNP-01) under Priority Review.
Viltolarsen, an antisense oligonucleotide, is designed to treat Duchenne muscular dystrophy patients amenable to skipping exon 53 – approximately 8% of the Duchenne patient population.
In addition to Priority Review, the FDA previously granted viltolarsen with a Rare Pediatric Disease Designation, Orphan Drug Designation, and a Fast Track Designation.
A decision on the application is expected from the FDA in July – September 2020.
Viltolarsen Clinical Trial Results
The NDA under review by the FDA includes results from a U.S./Canada Phase 2 study and its long-term extension, as well as a Phase 1 study and Phase 1/2 study that were conducted in Japan.
The U.S./Canada Phase 2 study, a placebo-controlled trial, was designed to evaluate the safety of viltolarsen in ambulant boys with a confirmed mutation in the DMD gene amenable to exon 53 skipping. In total, 16 boys were treated with viltolarsen once weekly for either 20 or 24 weeks (5 participants were randomized to placebo for 4 weeks).
Dr. Paula Clemens presented results from the trial at the Annual Congress of the World Muscle Society in October 2018. After 20/24 weeks of treatment, drug-induced dystrophin and exon 53 skipping efficiency were seen in both viltolarsen dose groups. Dystrophin levels, measured by western blot, averaged 5.8% of normal (range 1.1% – 14.4%). Results from timed function tests performed by patients treated with viltolarsen showed improvements in the 10-meter walk test, time to rise from supine, and the 6-minute walk test, compared to matched natural history controls. There were no adverse events that required discontinuation or a dose reduction.
All participants elected to enroll in the open-label long-term extension study of viltolarsen after completing the U.S./Canada Phase 2 trial. The extension study will evaluate the safety, tolerability, and clinical efficacy of viltolarsen at 80 mg/kg administered weekly for an additional 144 weeks.
The Phase 1/2 trial of viltolarsen in Japan, also a 24-week dose-ranging study, treated 16 boys with weekly infusions of viltolarsen at either 40mg/kg or 80mg/kg. Increases in Exon 53 skipping efficiency were observed in all 16 participants in the trial. Drug-induced increases in dystrophin were confirmed in 14 of the participants. There were no adverse events that required discontinuation or a dose reduction.
A Phase 3 Clinical Trial of Viltolarsen is Currently Recruiting
RACER53, a Phase 3 clinical trial to assess the efficacy and safety of Viltolarsen, is currently recruiting. The trial is seeking to recruit 74 ambulant boys, ages 4-8 years old, with a mutation in the DMD gene amenable to exon 53 skipping. Participants will be randomized to receive weekly infusions of Viltolarsen at 80 mg/kg or placebo for up to 48 weeks.
Additional information about RACER53, including trial site locations and contacts, is available on the study’s page in the rareClinical section of the DuchenneXchange.